Proposed is the design, development, fabrication, and testing of a Laser Lancing Device (LLD) as a minimally perturbing technique for collection blood from rats several times a day in sufficient quantities for measuring levels of hormone and of other circulating factors in young and old animals. The LLD system will allow painless and rapid (1-1.5 mIn.) taking of serial blood samples (up to 500 pL) from tails of unanaesthetized rats. The major innovation of this system is a laser diode perforator with adjustable power setting and focusing optics. The perforator will be capable of ablating only epidermis and a thin layer of papillary dermis with minimal photothermal and photomechanical damage to the surrounding tissue. It will produce a weak hemostatic effect and ensure fast wound healing. A heating cuff in the device will gently immobilize and warm the tail, increasing venous blood pressure there. Heparinized capillary pipettes and automated pipettes with heparinized tips can be used to collect and control the volume of the blood sample. In Phase I, a laser lancing device design and architecture for painless, repeated blood collection from laboratory animals will be investigated. PROPOSED COMMERCIAL APPLICATIONS: Compactness, low cost, and ease of integration with existing laboratory systems make the proposed device broadly useful in practically all fields of biomedical research based on animal models. Commercial applications include research laboratories, animals clinics, animal shelters, and veterinary control.